The present invention refers to a device at an intake system for internal combustion engines having elongated inlet manifolds to the engine cylinders, and where a return conduit for exhaust gases is provided between the exhaust side and the intake side of the engine, said return conduit being provided with a valve controlled by the engine speed or the like, whereby a connection flange is provided between the engine block and the intake manifolds, said connection flange being equipped with through openings for intake air to the engine cylinders, and with an exhaust channel arranged along the edge portions of the connection flange in the flange material, which exhaust channel via said valve is connectable to the exhaust side of the engine and along its extension being equipped with branch conduits, which communicate with the different through openings.
Such return of hot exhaust gases to the intake side of the engine is desired for reducing the combustion speed of the engine at certain operation conditions in order hereby to reduce the exhaust emissions at prevailing operation conditions.
GB-A-2 191 244 relates to such an exhaust gas recirculation system, where a spacer or connection flange is provided between the inlet manifold and the cylinder head, said spacer having air/gas flow passages extending therethrough and distribution passages for recirculated exhaust gases surrounding said air/gas flow passages and having inlet ports to said passages, the exhaust gas flow being controlled by a valve.
As it is a desire to change to plastic material in the inlet mainfolds it is less convenient to lead in the exhaust gases directly into such plastic tubes and such tubes are furthermore subjected to a substantial agening due to the heat they are subjected to at their connection to the engine wall.